As newer cryptocurrencies begin to creep up, law enforcement agencies want the same capabilities targeting the newer technology.

Launched in 2014, Monero is a cryptocurrency built fundamentally built to be private and untraceable. Zcash, a much-hyped 2016 addition to the cryptocurrency world, boasts similar privacy goals and is designed by a team of highly-respected academics in the U.S. and Israel.

“Monero in particular [is gaining adoption],” said Andrew Lewman, previously the director of Tor and now a vice president at the dark net intelligence firm DarkOwl. “One or two [criminal] marketplaces have played with Zcash but Monero is becoming much more popular and there is a marketplace that only does Monero now because bitcoin is easy to trace through the blockchain.”